1. Field of the Invention
The present invention relates to a laser beam type working method and apparatus for joining together metal conductors of a layer structure over a surface-side of a light transmitting substrate with an insulating layer provided therebetween, with the use of a laser beam.
2. Description of the Related Art
A liquid-crystal display, for example, is so formed as to have two light-transmitting sheet glass substrates arranged opposite to each other. One of the substrates has a plurality of thin-film transistors, plurality of pixel electrodes, plurality of drive wires, etc., formed, as a film pattern, opposite to the other substrate. A common electrode and color filter are formed on the latter substrate such that they face the former substrate. A liquid crystal is filled in a space between the two opposite substrates to provide a liquid crystal layer.
The film pattern-side substrate is called an array substrate having a circuit pattern around the film pattern. A check is made for a state of the film pattern.
In the manufacture of such a liquid crystal display, many steps are involved, such as a step for manufacturing an array substrate by forming a film pattern on a glass substrate and a step for checking the film pattern. Thin-film transistors on the film pattern are sometimes destroyed due to static electricity involved at the film pattern formation step and at a film formation step. In order to prevent an adverse effect from being exerted by static electricity on the thin-film transistor, a plurality of metal conductors are provided on the circuit pattern formation area such that they are electrically connected to each other. For a check to be made for the state of the film pattern, the metal conductors are electrically isolated from each other. At the end of a predetermined checking, the associated metal conductors are again electrically connected to each other, followed by a subsequent step or steps.